\begin{tikzpicture}
    \draw (0, 0) ellipse [x radius=3, y radius=1.2] node[below=1.6] {有理数集合};
    \draw (7, 0) ellipse [x radius=3, y radius=1.2] node[below=1.6] {无理数集合};
\end{tikzpicture}
